A conventional mattress cushion as a bed is constructed such that a number of coil springs are fixed to a metal frame under the both surfaces, overlaid by sheet materials respectively on upper and lower sides and covered by cloth entirely.
In such a kind of mattress, however, since a metal frame and a number of coil springs are incorporated, the gross weight becomes greater and handling is inconvenient. Also, the coil springs and metal frame are not only prominent causes of rust but also for breakage of the sheet material and the cover cloth, negatively affecting the durability of the mattress and the user's comfort.
Moreover, in this kind of bed mattress, as importance is laid only on how to support the body stably, the function of improving health is hardly considered,
It is the object of the invention to provide a light-weight mattress and improve the durability of the mattress, by forming a mattress cushion, particularly for a bed, without using a metal component such as a coil spring.
It is another object of the invention to improve the durability of the mattress cushion, the user's comfort and the health of the user by employing a core portion with a special structure.